2013 was supposed to be the year of solar maximum -- the peak of an 11-year cycle when the number of sunspots that mar the sun's surface is at its highest.

These sunspots, which are actually cool areas on the sun's surface caused by intense magnetic activity, are the sites of spectacular solar flares and CMEs, or coronal mass ejections, which can send billions of tons of solar material hurtling into space.

Sure, we've seen a handful of major solar flares, and a few extra fast CMEs, but scientists say our current solar maximum, known as solar maximum 24, is the weakest one in 100 years.

And some scientists believe that the 25th solar maximum could be even weaker.

To help us understand what's going on here, the American Astronomical Society asked three leading solar scientists to provide an update on the 24th solar maximum at a news conference Thursday.

It turns out there is some controversy in the scientific community about exactly why this year's solar maximum has been so unspectacular.

One theory is that this year's weak solar maximum is part of a 100-year solar cycle.

Graphs going back to the 1700s show that the number of sunspots during solar maximums in the early part of the last three centuries since humanity has been studying the solar cycle is much lower than the number of sunspots during solar maximums in the latter half of those centuries.

When asked what caused the 100-year cycles, the scientists admitted they did not know.

Other scientists are not convinced that this year's weak solar maximum is part of a 100-year cycle, and have not ruled out the possibility that the sun might be on the verge of a Maunder Minimum, a period of time when it exhibits almost no sunspots. The last Maunder Minimum was observed in 1645. However, the last time there was a Maunder Minimum, it was preceded by a relatively strong solar maximum.

Nobody knows exactly what is going on, because we've only been studying the sun for such a tiny sliver of its life, and so much of its behavior is a mystery.

[For the Record, 10:43 a.m. PDT, July 12: An earlier version of this online post said the American Astrological Society had asked solar scientists to discuss the solar maximum. It was the American Astronomical Society.]

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